[hawaiilover (OP)]

Answer for last week's challenge, Hemochromotosis

This week's case.

53 year old woman reports tremors, increased bowel movements and weight loss despite increased appetite.

Blood tests shows low levels of Thyroid Stimulating Hormone, (TSH) but elevated levels of TSI, Thyroid Stimulating Immunoglobulin, as well as TPO, Thyroid Peroxidase antibody and TSH receptor antibodies.

1 point for nameing general condition
1 point for nameing specific disease
1 point for nameing preferred treatment for specific disease

Good luck.

[chris]

This is thyrotoxicosis, an excess of circulating thyroid hormone (thyroxine). In this case the cause is Graves Disease, which is associated with the production of an antibody that triggers the thyroid to over-produce thyroxine.

Thyroxine determines metabolic rate and potentiates the action of adrenaline and adrenaline-like chemicals. Excess thyroxine causes tachycardia (fast heart rate) and arrhythmias (irregular heart rate), high blood pressure, intolerance of heat, increased appetite, weight loss, and proximal muscle wasting.

The secretion of thyroxine is under the control of the brain's pituitary gland, which releases a chemical called TSH (thyroid stimulating hormone). This is part of a negative feedback loop: TSH stimulates the thyroid to release thyroxine, which then shuts off the supply of TSH from the brain.

Occasionally, and more often in women, the body produces an auto-antibody that can bind to and activate the TSH receptor on cells in the thyroid. This bypasses the usual TSH control of thyroxine production and results in very low or undetectable TSH levels, because the excessive thyroxine in the blood stream shuts off TSH secretion. This is an important test to do because it rules out a problem with the pituitary (such as a tumour) producing too much TSH as the cause of the hyperthyroidism.

There are several ways to manage Graves Disease. The favoured option is known as block and replace. Patients are given an anti-thyroid drug known as carbimazole (or an alternative thyro-static called propylthiouracil), which suppress thyroxine production. This is continued for 6-9 months (with monitoring of thyroxine and supplementation where required).

The suppression is then withdrawn; in a number of patients the condition seems to abate. If several rounds of suppressive therapy fail then radio-iodine is given to ablate the thyroid, and the patient is given exogenenous thyroxine to take by mouth to maintain correct levels (using the TSH level to check whether they are being adequately medicated).

Chris

[iko]

Good show Chris!

BTW...did you get my message?   []

ikod

[chris]

Can I make a suggestion - let's have the medical challenges all in the same thread; otherwise people have to hunt around to find the old ones.

Chris

[kdlynn]

yes, that makes more sense. i didn't see the first two and was very confused when i saw week 3. i had to hunt a little.